Question

A charity is considering the possibility of having a benefit night at two different restaurants. The owner of the local Italian restaurant has offered to make a donation of $20 and $2 per diner that night. On the other hand, the owner of the Mexican restaurant has said he could contribute $30 plus $1 per diner. Based on the number of diners who have promised to participate in the event, it appears that each restaurant would donate the same total amount. How much would each restaurant donate?

Answer 1

Let's call the number of diners at the Italian restaurant x, and the number of diners at the Mexican restaurant y. We can set up the following system of equations to represent the problem:

Italian restaurant: $20 + 2x = $30 + $1y

Mexican restaurant: $30 + $1y = $20 + 2x

Subtracting $20 from both sides of the first equation and $30 from both sides of the second equation, we get:

Italian restaurant: 2x = $10 + $1y

Mexican restaurant: $1y = $10 + 2x

Multiplying both sides of the first equation by 1/2, we get:

x = $5 + $0.5y

Substituting this expression for x in the second equation, we get:

$1y = $10 + 2($5 + $0.5y)

Expanding the expression on the right side, we get:

$1y = $10 + $10 + $1y

Subtracting $1y from both sides, we get:

0 = $10

This equation is true, so the system of equations is consistent.

Since the total donations from each restaurant would be the same, we can set the total donations equal to each other and solve for the number of diners at each restaurant. The total donation from the Italian restaurant is $20 + 2x, and the total donation from the Mexican restaurant is $30 + $1y. Setting these expressions equal to each other, we get:

$20 + 2x = $30 + $1y

Subtracting $20 from both sides and $1 from both sides, we get:

2x - 2 = $10 + $1y - $1

Combining like terms on both sides, we get:

2x - 2 = $10 + $1y - $1

2x - 2 = $9 + $1y

2x - $9 - $1y = 2 - $9

2x - $1y = -$7

Dividing both sides by 2, we get:

x - $0.5y = -$3.5

Substituting this expression for x in the first equation, we get:

$20 + 2(-$3.5) = $30 + $1y

Simplifying the expression on the left side, we get:

$20 - $7 = $30 + $1y

Subtracting $20 from both sides, we get:

-$7 = $10 + $1y

Subtracting $10 from both sides, we get:

-$17 = $1y

Dividing both sides by -1, we get:

$17 = -$1y

Multiplying both sides by -1, we get:

-$17 = $1y

Dividing both sides by $1, we get:

-$17/$1 = $1y/$1

Simplifying the expression on the left side, we get:

-17 = y

Thus, the number of diners at the Mexican restaurant is -17, and the number of diners at the Italian restaurant is x = $5 + $0.5y = $5 + $0.5(-17) = $5 - $8.5 = -$3.5.

Since the number